Well no... there's nothing technically stopping them from supporting messages on mobile.

This is what they do on mobile:

* Lie to you about how many messages you have

* Ask you to install an app to see those messages

* Upon installing the app, give them permission to mine your data

Yes, it's a tactic to get you to install that app so they can mine your calls, texts, and contacts.

Right, the Messenger app that significantly slows down my phone and decreases it's battery life.

Yes, that's part of the horse shit.